Well depth-drilling mud analysis correlating system



W. W. BYNUM May 12, 1970 WELL DEPTH-DRILLING MUD ANALYSIS CORRELATING SYSTEM Filed Nov. 29, 1968 INVENTOR WINFRED W. BYNUM ATTORNEYS United States Patent Ofiice 3,512,164 WELL DEPTH-DRILLING MUD ANALYSIS CORRELATING SYSTEM Winfred W. Bynum, 3793 Greenway Place, Shreveport, La. 71105 Filed Nov. 29, 1968, Ser. No. 779,875 Int. Cl. G01d 9/00 US. Cl. 346-1 14 Claims ABSTRACT OF THE DISCLOSURE A system for correlating a drilling mud analysis 'with Well depth in which an analysis recording pen and a length of chart paper are moved forward a distance equivalent to one foot when the well depth is increased one foot and in which the recording pen is moved backward the same distance when the drilling mud lag time has elapsed after each advance. This keeps the pen in alignment with each section of paper until completion of the analysis of the mud corresponding to the section. A second pen carts the well drilling rate by recording the elapsed time between each paper advance.

BACKGROUND OF THE INVENTION During the construction of natural gas Wells, drilling mud is forced from the surface through the drill pipe and the drill bit and then back through the well to the surface. When the mud reaches the surface, it is analyzed as an aid in determining the presence and location of gas bearing deposits in the well. Because the mud does not return to the surface for a considerable period of time after it leaves the bit, often as long as several hours, it has heretofore been customary to chart the depth of the wall as a function of time and to separately chart the drilling mud analysis results as a function of time. The drilling mud analysis results are then hand correlated with the well depth on a third chart, a process that consumes a considerable period of time and is accordingly very expensive.

SUMMARY OF THE INVENTION A system for correlating an analysis of a fluid used in forming a hole with the depth of the hole as the hole is formed including an analysis receiving record and a recording instrument that is retained in alignment with each section of the record until completion of the portion of the analysis corresponding to that section. More particularly, the record and the instrument are advanced an incremental amount each time the depth of the hole is increased by a unit of depth and the instrument is retracted the incremental amount when the time necessary for the fluid to travel from bottom of the hole to the top has elapsed after the advance.

DESCRIPTION OF THE DRAWINGS A more complete understanding of the invention may be had by referring to the following detailed description when taken in conjunction with the drawing wherein a well depth-drilling mud analysis correlating system employing the invention is schematically illustrated.

3,512,164 Patented May 12, 1970 DETAILED DESCRIPTION Referring now to the drawing, there is illustrated a system 10 for correlating an analysis of drilling mud used in forming a natural gas well 12 'with the depth of the well. The well 12 is formed by a drilling system 14 including a derrick 16 used to support a string of pipe (not shown) terminating in a drill bit (not shown) terminating in a drill bit (not shown). The system 14 also includes equipment (not shown) for rotating the string of pipe and the drill bit to form the well 12 in the ground. During the drilling operation drilling mud (not shown) is forced into the well 12 through the string of pipe and the drill bit and then out of the well 12 along the outside of the string of pipe.

Drilling mud serves many functions in drilling operations, such as lubricating and cooling the drill bit, carrying drilling debris out of the well, etc. Since the drilling mud constantly flows through the well 12 it has become standard practice in the well drilling industry to analyze the drilling mud after it returned to the surface as an aid in locating gas bearing deposits in the well. Because the drilling mud requires a relatively long period of time, often referred to as lag, to return to the surface after it is used in the drilling operation, it has heretofore been impossible to correlate the analysis of the drilling mud with the depth of the well as the well is formed.

The system 10 includes a drum 18 having a line 20 wound upon it. The leading end of the line 20 extends over a pulley 22 on the derrick 16 and is connected to the string of pipe in the well 12. The length of the circumference of the drum 18 is exactly one foot so that the drum 18 revolves once each time the depth of the well 12 is increased one foot. The drum 18 supports a cam 24 that is positioned to close a switch 26 once during each revolution of the drum 18. The switch 26 operates to connect positive battery to a lead 28 and, accordingly, the drum 18 operates to apply a positive pulse to the lead 28 each time the depth of the well 12 is increased one foot.

The system 10 also includes a length of chart paper 30 which extends around a pair of drums 32 and 34 that are rotatably supported on a pair of parallel shafts 36 and 38, respectively. In the embodiment shown the length of chart paper 30 is of the endless variety; however, it should be understood that any desired form of recording device may be used in place of the length of chart paper 30. A toothed ratchet wheel 40 is secured to the end of the drum 32 and is mounted for engagement by a pawl 42 which is urged toward the ratchet wheel 40 by a spring 44. The pawl 42 is driven upwardly by a solenoid 46 each time a pulse is applied to the lead 28 and, accordingly, the length of chart paper 30 is advanced an incremental amount corresponding to a foot of well depth each time the depth of the well 12 is increased one foot.

The shaft 36 also rotatably supports a second ratchet wheel 48 which is attached to and drives the driving portion of a one-way clutch 50. The one-way clutch 50 in turn drives a chain 52 which extends around the oneway clutch 50 and around an idler sprocket 54 that is rotatably mounted on the shaft 38. A drilling mud analyzer 56 is attached to the chain 52 for movement thereby along a steadying backing plate 58. The analyzer 56 includes a marking pen 60 which extends from the analyzer 56 into engagement with the length of chart paper 30 and which operates to produce a record of the analysis of the drilling mud used in forming the well 12 on the length of chart paper 30.

A pawl 62 is mounted for engagement with the second ratchet wheel 48 and is driven toward the wheel 48 by a spring 64. The pawl 62 is driven upwardly by a solenoid 66 each time a pulse is applied to the lead 28 by the switch 26. The ratchet wheels 40 and 48 have the same diameter and the same number of teeth. Furthermore, the chain engaging portion of the clutch 50 has the same diameter as the drum 32. Therefore, each time a pulse is applied to the lead 28 the analyzer 56 is advanced an incremental amount that is exactly equal to the incremental amount that the length of chart paper is advanced. Thus, each time the depth of the well 12 is increased one foot the length of chart paper 30 and the pen 60 of the analyzer 56 are advanced together.

The system further includes a timing mechanism 68 comprised of endless magnetic belt 70 and three magnetic tape heads 72, 74 and 76. The belt 70 extends between an idler drum 78 and a power drum 80 that is driven by a motor 82, the speed of which may be controlled by -a variable resistor 84. The magnetic tape head 72 is a Write head which is connected to the lead 28 and which is actuated by the pulses applied to the lead 28 by the drum 18. Thus, the head 72 place a mark on the magnetic belt 70 each time the depth of the well 12 is increased one foot. The magnetic tape head 76 is a read head which operates to apply a pulse to a lead 86 whenever one of the marks placed upon the belt 70 by the read head 72 passes under it. The magnetic tape head 74 is an erase head which operates to clean the marks from the belt 70 before it passes under the head 72.

The pulses applied to the lead 86 by the head 76 are amplified by an amplifier 88 and then are directed to a solenoid 90. The solenoid 90 is connected to a pawl 92 which in turn is urged by a spring 94 toward a ratchet wheel 96. Whenever the solenoid 90 receives a pulse from the head 76 the pawl 92 is moved downwardly by the solenoid and the ratchet wheel 96 is rotated in a direction opposite to the direction of rotation of the ratchet wheel 48 under the action of the pawl 62.

Like the ratchet wheel 48, the ratchet wheel 96 drives a one-way clutch 98 which in turn drives a chain 100. Like the chain 52, the chain 100 extends around the clutch 98 and around an idler sprocket 102 pivotally supported on the shaft 38. The drilling mud analyzer 56 is attached to the chain 100 so that whenever the head 76 reads one of the marks on the belt 70 and the solenoid 90 is thereby actuated, the analyzer 56 and the pen 60 are retracted with respect to the length of chart paper 30, that is, the analyzer 56 is moved in a direction opposite to its direction of movement when a pulse if applied to the lead 28. The ratchet wheel 96 is of the same diameter and has the same number of teeth as the ratchet wheel 48 and the one-way clutch 98 is of the same diameter as the one-way clutch 50 so that each movement of the analyzer 56 toward the shaft 36 under the action of the ratchet wheel 96 is of the same length as the movements of the analyzer 56 away from the shaft 36 under the action of the ratchet wheel 48.

In addition to providing a correlation between the depth of the well 12 and an analysis of the drilling mud used in forming the well, the system 10 includes a subsystem 104 for recording the time required to drill each foot of the well 12 on the length of chart paper 30, that is, for charting the drilling time of the well 12. The subsystem 104 includes a motor 106 and a variable resistor 108 for controlling the speed of the motor 106. The shaft of the motor 106 is connected to the driving side of a tooth clutch 110, the driven side of which is connected to a drum 112. The drum 112 is urged toward the motor 106, and the clutch 110 is therefore normally engaged, by a combination compression and torsion spring 114 4 position between the drum 112 and a slow to operate solenoid 116. A cord 118 extends around the drum 112 and over three pulleys 120, 122, and 124 to a position adjacent the length of chart paper 30. A drilling time recording pen 126 is supported on the cord 118- in engagement with the length of chart paper 30.

When a pulse is applied to the lead 28 the slow to operate solenoid 116 moves the drum 112 away from the motor 106 against the action of the spring 114. This disengages the tooth clutch whereupon the combination compression and torsion spring 114 rotates the drum 112 to move the pen 126 to a position adjacent the lefthand edge of the length of chart paper 30. When the cam 24 recloses the switch 26 the solenoid 116 is deenergized and the combination torsion and compression spring 114 drives the drum 112 to the left, thereby engaging the clutch 110. The motor 106 then rotates the drum 112 which in turn moves the pen 126 to the right, against the action of the spring 114. When a pulse is again applied to the lead 28 the solenoid 46 is operated to advance the length of chart paper 30. Since the pen 126 is positioned at some point to the right of the lefthand edge of the chart paper 30, the pen 26 draws a longitudinal line indicative of the time elapsed since the last paper advance on the length of chart paper 30 as the length of chart paper 30 is advanced. After the completion of the advance of the length of chart paper 30, the slow to operate solenoid 116 again operates thereby disengaging the clutch 110. The spring 114 then revolves the drum 112 to return the pen 126 to the lefthand edge of the length of chart paper 30 whereupon the process is repeated.

In use, the variable resistor 108 is adjusted so that the pen 126 moves from the lefthand edge of the length of chart paper 30 to a predetermined maximum rightwardly position during the period of time contemplated as the maximum amount of time that will be required todrill any particular one foot segment of the well 12. The variable resistor 84 is adjusted so that any particular point on the belt 70 moves from the head 72 to the head 76 in a period of time equivalent to the lag of the drilling mud used in forming the well 12, that is, during the period of time necessary for the drilling mud to move from the bottom of the well 12 to the top. Then, the pen 126 operates to record the elapsed time between each advance of the length of chart paper 30 while the ratchet wheel 48 and the pawl 62 in combination with the ratchet wheel 96 and the pawl 92 operate to position the pen 60 in alignment with the section of the length of chart paper 30 corresponding to a particular depth of the well 12 while the drilling mud used in forming that depth of the well 12 is being analyzed.

The operation of the system 10 can be best understood by assuming two extreme conditions. First assume that during the drilling of a particular portion of the well 12 the drilling bit advances several feet during the time necessary for the drilling mud used in forming the first foot to move to the top of the well. The advance of the drill bit through several feet rotates the drum 18 through several revolutions which in turn applies several pulses to the lead 28. This operates the solenoid 46 and 66 several times which in turn advances both the length of chart paper 30 and the mud analyzer 56 several steps. Because the analyzer 56 is moved with the length of chart paper 30, the pen 60 of the analyzer 56 stays aligned with the same section of the chart paper 30 that it was aligned with at the start of the drilling of the particular portion of the well 12. Therefore, the pen 60 is positioned in alignment with the section of the length of chart paper 30 corresponding to the first foot of the portion of the well 12 when the drilling mud used in forming the first foot arrives at the surface to be analyzed.

Now assume that the drilling of the well 12 is discontinued but that the flow of drilling mud through the well 12 continues, an operation known in the drilling industry as circulating out. During such an operation the drum 18 is not rotated and accordingly no pulses are applied to the lead 2.8; Thus, the length of chart paper 30 is not advanced whatsoever and the analyzer 56 is not moved away from the shaft 36. However, since the belt 70 continues to rotate, the head 76 continues to apply a pulse to the solenoid 90 when a period of time equal to the drilling mud lag has elapsed after each advance of the paper 30 and the analyzer 56, and the solenoid 90 continues to retract the analyzer 56in response to each pulse. Since the analysis of the drilling mud used in forming a particular segment of the well 12 commences when the drilling mud lag has elapsed after the start of the drillingof that segment, this action moves the pen 60 into alignment with each section of the length of chart paper 30 at the start of the analysis of the drilling mud used in forming the portion of the well 12 corresponding to that section.

Of course, most drilling situations are a combination of the two situations described. That is, during most drilling situations the drill bit sometimes moves ahead rapidly so that a plurality of pulses are applied to the lead 28 between pulses applied to the lead 86 and sometimes moves slowly so that a plurality of pulses are applied to the lead 86 between pulses applied to the lead 28. Nevertheless, the system operates to maintain the pen 60 in alignment with the segment of the length of chart paper 30 corresponding to a particular foot of the well 12 while the drilling mud used in forming that foot of the well 12 is being analyzed by advancing the length of chart paper 30 and the pen 60 together each time the depth of the well 12 is increased one foot and by retracting the pen 60 when the drilling mud lag has elapsed after each advance.

Although only one embodiment of the invention is shown in the drawings and described in the specification, it will be understood that the invention is not limited to the embodiment described, but is capable of modification, rearrangement and substitution of parts and elements with' out departing from the spirit of the invention.

What is claimed is:

1. A method of correlating the results of an analysis of a fluid used in forming a hole with the depth of the hole including the steps of:

advancing a recording medium and a recorder device as the depth of the hole is increased, and

retracting the recording device into alignment with the section of the recording medium corresponding to a particular hole depth while the fluid used in forming that depth is analyzed.

2. The method according to claim 1 wherein the advancing step is characterized by advancing the recording medium and the recording device an incremental amount whenever the hole depth is increased a unit of depth and wherein the positioning step is characterized by retracting the recording device to the section of the recording medium corresponding to a particular depth at the start of the analysis of the fluid used in forming that depth.

3. The method according to claim 1 wherein the advancing step includes advancing the recording medium and the recording device an incremental amount whenever the depth of the hole is increased a unit of depth and wherein the positioning step includes retracting the recording device the incremental amount when the time necessary for the fluid to travel out of the hole has elapsed after each advance.

4. The method according to claim 3 including the additional step of recording the elapsed time between each advance of the recording medium.

5. In a recording device of the type including a recording medium and apparatus for recording the results of an analysis of a fluid used in forming a hole on the recording medium, a system for correlating the results of the analysis with the depth of the hole comprising:

means for advancing the recording medium and the recording apparatus an amount corresponding to a predetermined amount of hole depth each time the depth of the hole is increased the predetermined amount, and

means for retracting the recording apparatus to a position corresponding to a particular hole depth when the analysis of the fluid used in forming that depth begins.

6. The system according to claim 5 wherein the analysis of the fluid used in forming a particular hole depth begins a predetermined time after the depth of the hole is increased to that particular depth and wherein the retracting means includes means for retracting the recording apparatus the corresponding amount when the predetermined time has elapsed after each advance.

7. The system according to claim 6 wherein the retracting means includes timing means for producing a retraction initiating pulse the predetermined time after each advance.

8. A system for correlating the depth of a well and an analysis of the drilling mud used in forming the Well comprising:

a recording medium; 1

means for recording the results of a drilling mud analysis on the recording medium;

means for advancing the recording medium and the recording means as the depth of the well is increased; and

means for retracting the recording means a predetermined period of time after each advance.

9. The system according to claim 8 wherein the retracting means includes:

a recording member,

means for recording each advance of the recording medium and the recording means on the recording member,

means for reading the recording member and for initiating retraction of the recording means in response to each recording thereon, and

means for moving the recording member from the means for recording each advance to the means for reading the recording member during the predetermined period of time.

10. The system according to claim 9 wherein the advancing means moves the recording medium and the recording means an incremental amount in a certain direction each time the depth of the well is increased by a unit of depth, wherein the retracting means moves the recording means the incremental amount in the opposite direction and wherein the predetermined period of time is the time necessary for the drilling mud to travel from the bottom of the well to the top.

11. A system for correlating the depth of a petroleum well and the results of an analysis of drilling mud used in forming the well comprising:

a recording medium,

a drilling mud analyzer including an instrument for recording the results of the analysis on the recording medium,

means for monitoring the depth of the well and for 'advancing the recording medium and the instrument an amount corresponding to a preset amount of increase in the depth of the well each time the depth of the well is increased the preset amount, and

means for retracting the recording instrument the corresponding amount when the period of time necessary for the drilling mud to reach the top of the well has elapsed after the advance of the recording medium and the instrument.

12. The system according to claim 11 further including means for recording the elapsed time between each advance of the recording medium and the instrument on the recording medium.

13. Thesystem according to claim 11 wherein the instrument records the analysis by moving in a first direction and wherein the monitoring and advancing means advances the recording medium and the instrument and 7 8 the retracting means retracts the instrument in a second References Cited direction perpendicular to the first dil'fiction. P

14. The system according to claim 11 wherein the retracting mea s includes; Heck a recording member, 3,031,571 4/1962 Fearon 73 1s3' X 5 3,386,286 6/1968 Moore 73-153 meansresponsive to the monitoring means for marking the recordin member each time the de th of the we is increagsed the preset amount, P JOSEPH W. HARTARY, Prlmary Exammer means responsive to the marks on the recording mern- U S Cl X R ber for initiating retraction of the instrument, and 10 means for moving the recording member between the 73-153; 346-33, 118

marking means and the mark responsive means during the period of time. 

